Similarity Point
External (or positive) and internal (or negative) similarity points of two Circles with centers 
and 
and Radii 
and 
are the points 
and 
on the lines 
such that
or
- Helmholtz Differential Equation--Spherical Coordinates
- Helmholtz Differential Equation--Spherical Surface
- Helmholtz Differential Equation--Toroidal Coordinates
- Helmholtz's Theorem
- Helson-Szegö Measure
- Hemicylindrical Function
- Hemisphere
- Hemispherical Function
- Hempel's Paradox
- Hendecagon
- Henneberg's Minimal Surface
- Hensel's Lemma
- Henstock-Kurzweil Integral
- Heptacontagon
- Heptadecagon
- Heptagon
- Heptagonal Number
- Heptagonal Pyramidal Number
- Heptahedron
- Heptakaidecagon
- Heptaparallelohedron
- Heptomino
- Herbrand's Theorem
- Hereditary Representation
- Heredity